3sge - starts, idles, dies

i'll keep this as accurate and to the point as i can.

i will start up my car (3sge in an aw11). after it warms up, it will idle for 2-3 minutes, then die.

the coolant level is fine, the fuel level is fine, the injectors are all good. there is plenty of oil in the engine. the battery is good.

a friend suggested that it might be the IAC (idle air control valve). i believe he means the VSV that is nearest the throttle body, under the intake manifold.

so, does anyone have experience with this? has anyone had something similar? any other recommendations of what to inspect?

 

all of the hoses leading from the bottom of the throttle body to their respective ports, are new - and everything has been clamped. i will double check everything, when the rain stops.

the IAC valve is roughly $82. so, if i have to get another, then i'll get it.

again, the engine will idle smoothly and without issue for 2 to 3 minutes with zero throttle input. only after that time, does it die out. i can restart it right away, and it'll idle fine for a bit.

again, once the rain stops, i'll re-check all of my findings and test it again, just to be sure that i'm not mistaken.

 

that is something that i fully intend to test tomorrow. i will report back my findings.

brand new NGK plugs (i prefer Denso) - 0 miles on them. i will pull them and check them tomorrow.

 

could not test it today - battery is nearly dead. going to get a new battery, but for the moment, recharging the current one.

will test it out tomorrow.

 

thanks for the input. unfortunately, that isn't it. i did accidentally try to start it twice with the AFM disconnected. it would turn over, idle for 1 second, then die.

in my scenario, it will idle stably for about 2 to 3 minutes solid... then die.

 

yeah, it is a weird problem.

i did not purchase a new IAC - it is the original that came with the engine. are those known for going out or failing?

i don't know what you mean by fuel pump/pressure playing up... could you elaborate please?

the coolant was a BIT low - maybe a few cups worth of coolant at most. not something that i think would cause this sort of issue, but i might be wrong.

when i did this, the temp gauge DID go a bit past half, but then dropped back to just before half (ie. normal). moments later, it died.

so... as luck would have it, tomorrow is wide open with nothing planned... so, i'll be working on my Mr2 tomorrow. i'll report back my findings - be they good or bad.

 

i did check the coolant level, and it was lower than last time. so, i topped it off and squeezed the coolant hose a bit to get it moving/filled as much as possible.

i connected the freshly charged battery - the interior lights and dash clock turn on (acc). when i rotate the key to the 'on' position, everything goes dim (the parking brake light is BARELY visible) and it will not crank over. i have disconnected and reconnected every bit of the harness from the ECU, etc. no change. i did bring out my multimeter and tested - i am getting 12.8v to the primary + lead that goes into the engine bay.

so... very strange.

anywho. i removed the TVIS switch and Idle Up vacuum switch assembly.





the problem is that now i have a broken TVIS switch.

also, when i tried blowing air through the Idle Up vacuum switch, no air would pass through in either direction. i test it for continuity - none. i tested it for resistance and it came back with 0.3 ohms or 0.03 ohms (i forget which, but it was the same as the TVIS switch).

so... if anyone has this assembly for sale, and it is tested to be good, i'm willing to buy it. just contact me (not12listen at gmail dot com).

 

i'll retest both sensors, just to make sure that i was reading them correctly. i've not seen any of the TVIS switches setup identical/similar to these, but i've also not looked at them in such detail. i'll recheck all of my 4age/aw11 stuff to see if any matches.

the grounds have not changed since the last time when it did start, so i'm very confused. also, when i did not have the correct ground setup originally, it would still turn over - just very slowly. this is no turn over at all.

i really want this sorted too... it's been far too long... there will be video and thanks for the note of confidence on the choice of engine.

 

and so the plot thickens...

i just tried to start it again. nothing. but, it gets more interesting!

now i get ZERO dash lights (other than the tiny light that illuminates the gauge cluster from the side) - no brake light, no check engine light, no voltage meter and no fan in the engine bay. every time i step on the brake pedal, the clock resets.

i've checked every fuse in the front trunk, kick panel and engine bay - every fuse is good.

so, either a fried a relay or i developed a massive ground where one should not be.

this is frustrating and confusing... so... how do i test a relay? i'll pull each one and test each one.

 

it is really puzzling, as i have no radio/cd deck or speakers currently, no interior or exterior lights are on... my transmission's reverse light is not even wired up at all.

i am not aware of any fuseable links - i'll have to start looking.

at one time, i did see a bit of smoke come from the + wire that leads to the fuse box. i did unwrap the lead, clean both surfaces, then re-wrap everything again (electrician's tape - multiple layers). never smoked again and it did start afterwards.

that is a bit much to read at this moment (just woke up) - i'll go over this this evening. many thanks for the assistance and info!

absolutely agreed. i've checked, re-checked and triple checked all of the battery connections and the main ground connections too. my battery is in the front trunk, with a 0 gauge wire leading into the passenger cabin, then into the engine bay. i've checked the voltage at the battery - 12.8v. i then checked the voltage level in the engine bay - 12.8v. so, i can guess that i've not developed a short along that path.

2 friends have suggested that i might have burned out my ignition switch (in the steering column). so, they've both recommended leaving the battery connected as normal, then temporarily jumping a lead to the + side of the starter (key in the ON position). if it cranks over and (potentially) starts, then it would point at the ignition switch having fried.

does that sound reasonable?

 

a described my issue to a friend off in New Zealand... his recommendation is to check all of the grounds. so, this evening i'll be hunting for my 0 gauge wire. if i can find it, i'll be making myself some new ground wires for the battery and transmission (and anywhere else that seems logical).

if that solves it, i'll be ecstatic! if not, then i'll try bypassing the ignition switch... if that still doesn't take care of it, well then i'll be traveling along a creek without a paddle.